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Y Y Wai

Publications and source records attributed to Y Y Wai.

At least 19 recordsLinked to original sources
PubMed2005

Cortical dysplasia associating with abnormal vasculature complicated with subdural haemorrhage.

Cortical dysplasia is a neuronal migration disorder occasionally associated with anomalous draining veins. However, to our knowledge, no intracranial haemorrhage in conjunction with this association has been reported in the literature. We herein report a 7-month-old baby girl with cortical dysplasia associated with an ipsilateral cortical draining vein and complicated with subdural haemorrhage, with the diagnosis made by computed tomography and magnetic resonance imaging. This case demonstrated that patients with this condition could have an excellent prognosis even when the anomalous veins coexist with intracranial haemorrhage. We postulate that venous rupture may be the cause of this condition and further discuss the possible pathophysiology.

Central Nervous System Vascular Malformations↗
PubMed2001

Proton magnetic resonance spectroscopy of cerebral glioma after irradiation.

BACKGROUND: Conventional magnetic resonance imaging (MRI) is commonly employed to assess cerebral gliomas after radiotherapy, but it cannot always differentiate tumor regrowth from post-irradiation changes. In this study, we utilized magnetic resonance spectroscopy (MRS) to evaluate changes in cerebral metabolites in patients with a cerebral glioma after irradiation. METHODS: Over a period of 3 years, we performed MRS after MRI whenever soft tissue masses were found on magnetic resonance (MR) images. A total of 122 MR spectra of 58 patients was used for analysis. Spectral interpretations were based on integral values of the N-acetylaspartate (NAA) and choline (Cho) compounds relative to phosphocreatine/creatine (Cr). RESULTS: Our MRS study showed that higher Cho/Cr ratios occurred in regrowing gliomas than for stable diseases (range, 0.9 to 9.5 vs. 0.4 to 2.1; mean, 3.0 vs. 1.2). A greater increment in the Cho/Cr ratio between successive studies was also noted in regrowing gliomas than for stable disease (range, 41% to 87% vs. < 32%). No significant differences in NAA/Cr ratios or lactate were found between these 2 groups. None of our patients exhibited abnormal MR spectra in the mirror area of the contralateral brain. CONCLUSION: MRS provides valuable information about the metabolism of irradiated gliomas and can be used to exclude radiation encephalopathy of the contralateral brain. Cho is the most reliable indicator of a regrowing glioma. A high Cho/Cr ratio or substantial elevation in the Cho/Cr ratio between serial studies increases the likelihood of tumor regrowth. However, lower Cho/Cr ratios were inconclusive for determining if tumor regrowth or a stable process was occurring.

Brain↗
PubMed1998

Comparison of cerebral occipital gray and parietal white matter metabolite differences using PRESS and STEAM at different echo times.

BACKGROUND: Reports regarding the differences in metabolite ratios with different echo times (TEs) at various brain regions are rare. The purpose of this study is to investigate in Chinese the cerebral metabolite ratios in gray matter (GM) and white matter (WM) using both STEAM and PRESS techniques at TEs of 30 ms and 136 ms, respectively. MATERIALS AND METHODS: Using GE Signa 1.5 T Scanner with STEAM and PRESS sequences, automated single voxel localized proton magnetic resonance spectroscopy (1H-MRS) were applied to identify the metabolite ratio differences in cerebral parietal white and occipital gray matter of healthy volunteers. RESULTS: Metabolite ratios between GM and WM were significantly different in N-acetyl aspartate/creatine (Cr), choline/Cr and myo-inositol/Cr. There were also significant differences in metabolite ratios when different echo times were applied. CONCLUSION: Reliable metabolite ratios at different brain regions can be obtained using automated data acquisition and spectral processing in single voxel localized 1H-MRS. This technique may remove user-dependent bias and provide more efficient and consistent ways to analyze the spectral data. However, one must be careful in interpreting spectroscopic data based on different regions and acquisition parameters.

Adult↗
PubMed1997

CT angiography of intracranial aneurysms: advantages and pitfalls.

OBJECTIVE: To determine the clinical usefulness of computed tomography (CT) angiography in the evaluation of cerebral aneurysms. MATERIALS AND METHODS: From October 1994 through April 1996, 26 patients with 30 surgical proven intracranial aneurysms underwent both CT angiography and catheter cerebral angiography. The findings of the two methods were reviewed independently and then compared with each other. RESULTS: Comparing with catheter angiography, CT angiography was superior in demonstrating the aneurysmal neck in seven aneurysms but was inferior in one. The thrombosed part and calcification of aneurysms were clearly demonstrated on CT angiograms. CT angiography also aided in differentiating tight vascular loops from aneurysms. On CT angiograms, one posterior communicating arterial aneurysm was overlooked and another anterior choroidal artery aneurysm was misinterpreted as a posterior communicating artery aneurysm. Of note were two patients in whom the infundibulum of the orbitofrontal artery was misinterpreted as the anterior communicating artery aneurysm. CONCLUSION: CT angiography can compliment conventional catheter angiography for its better demonstration of the 3-dimensional anatomy. It can provide surgical information about the neck, calcification and thrombosed part of an aneurysm and its relation to adjacent structures. However, caution is advocated because CT angiography may fail to demonstrate small but important vessels such as posterior communicating, anterior choroidal and orbitofrontal arteries. Recognition of the limitations of CT angiography is important in minimizing interpretation errors.

Adult↗
PubMed1996

Tuberculoma en plaque: CT.

A 35-year-old woman presented with a 6-month history of intermittent headaches, vomiting and dizziness. CT showed a plaque-like mass with tiny calcifications along the surface of the left frontal lobe. The mass exhibited heterogeneous enhancement with a few low-density foci. Underlying sulcal obliteration and enhancement and white matter oedema were also noted. Histopathological examination of excised material was consistent with tuberculoma. Recognition of this unusual presentation of intracranial tuberculoma may facilitate appropriate diagnosis and management.

Adult↗
PubMed1995

Congenital extracranial meningioma.

The authors report a case of congenital meningioma in a newborn. This tumour is extremely rare and only six cases have been reported in the literature. Those reported cases were mainly intracranial. This is the first case of a neonatal extracranial meningioma that was evaluated preoperatively by computed tomography and magnetic resonance imaging.

Humans↗
PubMed1995

Mitochondrial encephalomyopathies: CT and MRI findings and correlations with clinical features.

Seven patients (3 men, 4 women; age 15-48 years) from 6 families with mitochondrial encephalomyopathies were studied. There were 4 patients with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) and 3 patients with myoclonus epilepsy and ragged-red fibers (MERRF). The clinical course was variable in both MELAS and MERRF patients. Interestingly, one MERRF patient had putaminal hemorrhage with left hemiplegia. In MELAS patients, brain computed tomography (CT) revealed cerebral hypodensity lesions affecting all four lobes and relative sparing of the basal ganglia and the thalamus. The CT of MERRF patients showed cerebral and cerebellar cortical atrophies in two and ventricular dilatation in one. During the recovery stages, magnetic resonance images (MRI) revealed subcortical white matter lesions in two MELAS patients and one MERRF patient. These subcortical white matter lesions were most prominent in the paraventricular areas. The present data indicate that in MELAS the hypodense lesions tend to affect the cerebral hemisphere and to spare the subcortical gray matter. Furthermore, the involvement of the paraventricular white matter may occur in both MELAS and MERRF.

Adolescent↗
PubMed1995

Isolated cortical venous thrombosis--discrepancy between clinical features and neuroradiologic findings. A case report.

Isolated cortical venous thrombosis (CVT) is rare, and the discrepancy between clinical features and neuroradiologic findings has not been adequately emphasized. A thirty-one-year-old woman presented with focal seizures and occasionally secondary generalization. There was no focal neurologic deficit except for Todd's paralysis. Electroencephalography showed intermittent theta waves at the left frontoparietal area. Brain computed tomography (CT) and magnetic resonance imaging (MRI) disclosed a large lesion in the left frontoparietal area. An extensive occlusion of the superior cerebral veins of the left hemisphere with a patency of the dural sinuses was noted in the cerebral angiography. Eight months later, the CT hypodense lesion disappeared. Her neurologic status was stationary, but the seizures, mostly focal, still occurred occasionally. In this report, the authors emphasize the dissociation between minor clinical features and larger CT and MRI lesions in isolated CVT.

Adult↗
PubMed1995

Common carotid artery occlusion: evaluation with duplex sonography.

PURPOSE: To demonstrate the efficacy of carotid duplex ultrasound to diagnose common carotid artery occlusion (CCAO) and to define the clinical features of CCAO. METHODS: We reviewed 5400 carotid duplex ultrasonograms obtained over a 7-year period for suspected carotid artery disease. In cases of CCAO, medical records were reviewed. RESULTS: Thirteen cases (0.24%) of CCAO were diagnosed by carotid duplex ultrasonography, including five cases of isolated CCAO. Seven cases were proved by cerebral angiography. Cerebral angiography failed to demonstrate patent internal carotid arteries in two cases of isolated CCAO. Mean age of onset was 67 +/- 9 years. The main clinical presentation was stroke in nine cases (69%). The most common vascular risk factors were hypertension (62%) and heart diseases (54%). Three patients had a history of radiation therapy to the neck. Two of five patients with isolated CCAO had major stroke, with good recovery in one, whereas five of eight patients with CCAO had major stroke; among them, only one had good recovery. CONCLUSION: Patients with isolated CCAO may have a better outcome than patients with CCAO. Duplex sonography, particularly with color-coded flow imaging, provides an accurate examination to define the patency of the arteries distal to the carotid bifurcation. The clinical features of CCAO are similar to those of internal carotid artery occlusion except for the low prevalence of CCAO.

Aged↗
PubMed1994

Intramedullary spinal tuberculomas during treatment of tuberculous meningitis.

A case of multiple intramedullary spinal tuberculomas developing paradoxically during effective treatment of tuberculous meningitis is described. Serial MR imagings with Gd-DTPA enhancement studies showed initial homogeneous enhanced lesion representing myelitis or the early tuberculoma stage, which evolved to show ring enhancement with hypointense center later. Their appearance was similar to those described in brain tuberculoma. Gd-DTPA enhancement MR imaging is more sensitive than MR imaging without enhancement in demonstrating the lesions of tuberculoma and arachnoiditis. Antituberculous medication was effective with marked clinical improvement.

Adult↗
PubMed1993

Overlapping syndrome of MERRF and MELAS: molecular and neuroradiological studies.

We describe a 42-year-old woman with overlapping syndrome of MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) and MERRF (myoclonus epilepsy and ragged-red fibers). Clinically, she had episodic headache, stroke-like episode with left hemiparesis and lactic acidosis commonly found in MELAS syndrome. However, myoclonus seizure, and ataxia with dyssynergic gait characteristic of MERRF were also noted. Computed tomographic scans showed a right temporo-parietal hypodense lesion. The lesion disappeared 20 months later, even magnetic resonance images also failed to reveal this abnormality. A molecular analysis of mitochondrial DNA was conducted by using restriction endonucleases ApaI and NaeI. A transition from A to G was found at the nucleotide position 3243, but not found at the 8344th nucleotide pair. In this report, we document the fluctuating CT changes and emphasize the importance of molecular analysis in patients with overlapping syndrome of mitochondrial encephalomyopathies.

Adult↗
PubMed1993

Arachnoid cyst of the lateral ventricle manifesting positional psychosis.

A 30-year-old woman had an arachnoid cyst in the trigone of the right lateral ventricle 5 years before she developed episodic auditory and visual hallucinations as well as delusions of persecution. The psychotic episodes tended to occur after the patient had lain in bed for 1 to 2 hours. After craniotomy and wide excision of the cystic membrane, draining the cystic fluid to the lateral ventricle, the psychotic episodes subsided in a follow-up period of 6 months. We believe that when the patient was recumbent, the trigone cyst blocked the temporal horn further, caused local ischemia, and triggered the psychosis, which was a form of partial complex psychomotor seizure.

Adult↗
PubMed1992

Bilateral glossopharyngeal neuralgia after excision of a solitary cervico-medullary haemangioblastoma: case report.

A man presenting with sleep apnoea was found to have a haemangioblastoma at the cervico-medullary junction. The associated hydrocephalus and syringomyelia resolved after excision of the tumour. Postoperatively the patient developed transient bilateral glossopharyngeal neuralgia, presumably due to surgical damages to the tractus solitarius. To the best of our knowledge this is the first reported case with transient bilateral glossopharyngeal neuralgia following resection of a haemangioblastoma of the cervico-medullary junction.

Adult↗
PubMed1992

Intracerebral malignant fibrous histiocytoma: case report and review of the literature.

A 50-year-old woman developed an intracerebral malignant fibrous histiocytoma at the site of a previously clipped aneurysm in the right temporal lobe. This tumor rarely originates within the brain. Review of the literature suggests that postoperative and/or postirradiation effects may contribute to the growth of this particular tumor.

Brain Neoplasms↗
PubMed1992

Spontaneous intracerebral hematoma from occult carotid-cavernous fistula during pregnancy and puerperium. Case report.

In most cases, intracerebral hemorrhage during pregnancy or puerperium results from cerebral aneurysms or arteriovenous malformations. The authors present a case of a 30-year-old woman whose symptoms from a traumatic carotid-cavernous fistula had completely resolved 1 1/2 years after the event, but recurred 4 years later, causing two hemorrhages during pregnancy (33rd and 35th week of gestation) and one during the postpartum period (10 days after Caesarean section). Partial thrombosis of the cavernous sinus with obliteration of most of the drainage from the fistula accounted for the resolution of clinical symptoms, but also promoted back-flow to the preserved drainage of superficial cortical veins. The hemodynamic changes and the hormonal effects due to the patient's subsequent pregnancy further aggravated the venous engorgement and finally caused rupture. All three hematomas occurred in the vicinity of the extremely dilated veins, suggesting that back-flow with venous hypertension was the probable cause for the intracerebral hematomas. Spontaneous healing of the carotid-cavernous fistula should be confirmed with cerebral angiography.

Adult↗
PubMed1992

Hypothalamic amenorrhea in a case of mitochondrial encephalomyopathy.

A 26-year-old female with myoclonus epilepsy associated with ragged-red fibers is reported. Clinically, she had myoclonus epilepsy, cerebellar ataxia, a bilateral neurosensory type hearing loss, retinitis pigmentosa and short stature. She also presented with primary amenorrhea and poor development of secondary sexual characteristics. Endocrinologic studies revealed that hypothalamic dysfunction was the most plausible cause of her primary amenorrhea. Magnetic resonance imaging showed marked dilatation of the third ventricle indicating thalamic and hypothalamic degeneration. We conclude that hypothalamic dysfunction may be one of the characteristic features of mitochondrial encephalomyopathies.

Adult↗
PubMed1990

The association of arteriovenous malformation and aneurysm within the posterior cranial fossa--report of a case.

A relatively rare case of cerebellar arteriovenous malformation (AVM) associated with a saccular aneurysm fed by the left posterior inferior cerebellar artery (PICA) is described. The interpretation of angiograms and the appropriate surgical treatment for the coexistence of the intracranial AVM and aneurysm are discussed. It is a fact that the steal phenomenon existed in the flow of contrast medium during the angiography. The appropriate surgical treatment may be clipping of the aneurysmal neck first and then radical excision of the AVM.

Adult↗